The Torah states that any land animal that chews its cud and has cloven hooves is kosher (Leviticus 11:3). Similarly, a short list of criteria — the presence of fins and scales — allows us to identify kosher fish (Leviticus 11:9). But as a mishnah on yesterday’s daf notes, the Torah does not outline general principles for identifying kosher birds. Instead, it simply provides a list of 24 forbidden birds (Leviticus 11:13–19) — leaving open the question of whether there are general principles that can help us distinguish kosher from unkosher avian species.
In lieu of more explicit Torah guidelines, the rabbis derive criteria based on the list in Leviticus, which begins with the nesher. This is the modern Hebrew word for eagle, and also how many English Bible translations render it in this context. Commenting on Micah 1:16, Rashi suggests that a nesher lacks feathers on its head (talk about a bald eagle!), which hints that it’s some kind of vulture. This is supported by Job 39:30, which indicates that a nesher feeds on corpses. Regardless of the precise identification, which remains a subject of debate, the rabbis derive the signs for determining whether a bird is permitted from this particular species:
Just as the nesher — which is unique in that it has no extra digit or crop, its gizzard cannot be peeled, and it claws its prey and eats it — is unkosher, so too all birds with these four signs are unkosher.
And just as doves and pigeons — which have an extra digit and a crop, and whose gizzard can be peeled, and who do not claw their food and eat it — are kosher, as they are fit for sacrifice on the altar (see Leviticus 1:14), so too all birds with these four signs are kosher.
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For the Gemara, the nesher becomes the epitome of an unkosher bird, while doves and pigeons (which are also offered on the altar) are the premier examples of kosher birds. The Gemara identifies four “signs” that distinguish these species. Clawing one’s prey is the first sign — and it always renders a bird unkosher. The other three signs are not behavioral but anatomical: a crop (a pouch at the base of the throat for storing chewed food), an extra digit (an elongated toe at the back of their foot), and a gizzard whose lining can be peeled by hand. The nesher has none of these three anatomical signs; pigeons and doves have all of them.
But what if your bird has some qualities like a dove and some like a nesher? Is it kosher?
Rabbi Hiyya teaches: A bird that comes before a person with one sign, and which is not listed in the Torah as unkosher, is kosher, since it is unlike a nesher. The verse mentions the nesher specifically to indicate that it is only a bird like a nesher, which has none of the signs of a kosher bird, that you shall not eat. But if there is a bird that has even one of the signs, you may eat it.
Clawing one’s prey is a disqualifying attribute in any bird, regardless of the other anatomical signs. But according to Rabbi Hiyya, kosher birds need not have all three of the other signs: a crop, an extra digit and a peelable gizzard. If a non-clawing bird has just one of the other three signs, says Rabbi Hiyya (and Maimonides later concurs), it is still kosher.
Most halakhic guides say that the best way to determine whether a bird is permitted is to consult a list — either the Leviticus list of forbidden birds or a list of commonly consumed birds in one’s community. But absent such a list or an expert who can provide an answer, these guidelines give individuals the tools to determine for themselves whether a particular bird may be eaten.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on June 30, 2026. If you are interested in receiving the newsletter, sign up here.
